Medieval cathedrals often had a labyrinth in the nave. These labyrinths are not mazes: they do not branch. Rather, they are a long line twisted to form a circle. Pilgrims who could not go to Jerusalem could, instead, follow the labyrinth (on their knees!) to the center, which represented the earthly Jerusalem. The labyrinth at the cathedral of Chartres is still walked by pilgrims, but I didn't see any on their knees.